This invention relates to means for mounting a magnetic deflection yoke on the neck of a cathode-ray tube and particularly to an adjustable mount utilizing a plurality of adjustable springs.
Cathode-ray tubes, such as color television picture tubes, require a magnetic-deflection yoke mounted on the outside of the tube envelope. The yoke comprises horizontal and vertical deflection coils together with a suitable core. During operation of the tube, the yoke field deflects electron beams within the tube in both the vertical and horizontal directions thereby causing the beams to scan the viewing screen of the tube.
Several structures have been proposed for mounting and holding the yoke in a desired position on the tube. In one structure, the yoke is placed in a housing which is in turn positioned on and glued to the tube. In another structure, the housing is clamped on the tube and the yoke is positioned within the housing and clamped in place. In a third structure, a platform first is glued to the outside of the tube and then the yoke and housing are positioned over the tube and clamped to the platform. An improved structure is presented in U.S. Pat. No. 3,786,185 issued to me on Jan. 15, 1974. This patent discloses a combination including a platform affixed to a cathode-ray tube by an adhesive and a yoke housing enclosing a portion of the yoke. The platform has a plurality of projections that are secured within indentations in the yoke housing.
A disadvantage shared by all of the foregoing yoke mounting structures is that once they have been attached to a tube, further adjustment of yoke position is not possible without losing the entire alignment of the yoke relative to the tube. Furthermore, in those yoke mounting schemes requiring permanent attachment of the yoke to a tube, once the adhesive has set, the mount may be destroyed when the yoke is removed. Therefore, there is a need for a permanently affixed mount that provides means permitting minor adjustments of the yoke after the mount is attached to a tube.
The present invention maintains many of the advantages of prior art structures while providing means that permit minor adjustment along one axis while maintaining rigidity along another axis.